1. Field of the Invention
The present invention relates to a bidirectional battery power inverter as set forth in the preamble of claim 1 and claim 2.
2. Description of the Prior Art
Bidirectional power inverters serve on the one side to convert a DC battery voltage from 12 volt into a 50 Hz or 60 Hz AC voltage of e.g., 230 volt, on the other side however also to charge the battery from the AC voltage. The energy flows both from the battery to a DC-AC converter and from the DC-AC converter to the battery. The problem arising here is that the conduction losses are quite high at such small DC voltages.
A power inverter with a half-bridge array on the primary side and a full bridge array on the secondary side is known from the document EP 0 820 893 A2.
A bidirectional DC-DC converter is known from EP 1 458 084 A2. It includes a bridge circuit on the input side, a bridge circuit on the output side and a transformer connected between said two circuits, said transformer having a resonant capacitor and a resonant inductor.
A DC-AC converter having a transformer, which comprises two windings with center tap on the primary side, is connected to a power electronic midpoint circuit with semiconductor switches and comprises a winding on the secondary side, is shown and described in U.S. Pat. No. 6,507,503 B2.
Further converter circuits have been disclosed in the document DE 40 13 506 A1 and in U.S. 2003/0142513 A1.